C5- Input and Output, The User Connection
How Users See Input and Output

Users submit data (input) to the computer to
get processed information (output)
 Output
can be instant reaction to input
 Also can be separated by time, distance, or both
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Instant Reaction

Items scanned at supermarket


Produce item name and price at
counter
Forklift obeys operator’s commands
Characters displayed as “typed” text
and stored in pad
Factory workers punch a time
clock as they go from task to task

Produce weekly paychecks and
management reports
Data on checks input into bank
computer


Sales rep enters an order on a pad



Forklift operator speaks to
computer


Input and Output Separated
Charge-card transactions
provide input


Computer processes entries
once a month to prepare
statements
Processed monthly to produce
customer bills
Water samples collected and
input into computer

Used to produce reports that
show patterns of water quality
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User Input: Getting Data using keyboard

Similar to typewriter keyboard
 May
be part of a personal computer
 May be part of a terminal connected to a computer
in another location

Can be unique to an industry
 Keys
on McDonald’s keyboards represent Big Mac
or large fries

Ergonomic keyboards
Pointing devices
Source data automation
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Anatomy of a Keyboard
Designed to reduce or minimize repetitive
strain injury of wrists
Provide more natural, comfortable
position of wrists, arms, and hands
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User Input: Getting Data using Pointing Devices
Used to position a pointer on the screen
 Communicate commands to operating system
by clicking a button
 Common devices

 Mouse
 Devices
used for games
 Devices used in laptops
 Others
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Mouse

The most common pointing
device


Movement on flat surface
causes movement of pointer
on screen
Several types



Mechanical - small ball on
underside rolls as mouse is
moved
Optical - uses a light beam to
monitor mouse movement
Cordless - uses either
infrared or radio waves,
rather than a cord, to
connect to computer
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Trackball and Joystick

Trackball




Variation on mechanical
mouse
User rolls the ball directly
Often built into laptop
computers
Joystick



Short lever with handgrip
Distance and speed of
movement controls
pointer’s position
Pressing trigger causes
actions to take place
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Touchpad and Pointing Stick

Touchpad




Rectangular pressuresensitive pad
Sliding finger across
pad moves pointer
Tapping with finger
recognized as click
Pointing stick


Small pressuresensitive post mounted
in center of keyboard
Pushing post in any
direction moves pointer
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Other Pointing Devices

Graphics tablet



Touch screen




User moves stylus or puck
across board
Used to create or trace precise
drawings
Allow user to touch items on
screen
Position of finger on screen
determines item to be input into
system
Used at kiosks in public places
such as malls
Pen-based computing


Use pen-like stylus to input data
Often used in PDAs or pocket
PCs
Return
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User Input: Getting Data using Source Data
Automation
Use of special equipment to collect data at the
source
 Primary areas

 Magnetic-ink
character recognition (MICR)
 Optical recognition devices
 Other sources
Return
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MICR
Uses a machine to
read characters
made of magnetized
particles
 Banking industry is
predominant user

Characters preprinted
on lower left-hand
side of check
 Amount added by
MICR inscriber when
check is cashed

Return
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Optical Recognition
Uses a light beam to scan data and convert to
electrical signals
 Common uses
 Scanners are the most common form
 Other optical recognition methods

Return
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Common Uses


Scanners at supermarkets
Document imaging - converts
paper documents to
electronic versions


Documents stored on disk
Can be edited or processed by
software
Scanners

Flatbed scanner



Sheetfed scanner


Motorized rollers feed sheet
across scanner head
Handheld scanner


Typically scans one page at a
time
Can be used to scan large bound
documents
Smallest and least accurate
Optical character recognition
(OCR) software required to
convert picture into characters
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Other Optical Recognition Methods

Optical Mark Recognition


Optical character
recognition


Machine senses marks on
piece of paper
Wand reader reads
characters in special
typeface
Bar Codes


A series of vertical marks
Represents a unique code

Universal Product Code
(UPC) used as standard in
supermarkets
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Voice Input

User speaks to computer




Most are speaker-dependent


Speech recognition devices
convert spoken words into
binary digits
Digital Camera

System “learns” user’s voice

Types of systems


User takes photo that is stored
on a chip
Photo can be downloaded to
computer
Discrete word systems - user
must pause between words
Continuous word systems user can speak normally


Use photo-editing software to
enhance
Store permanently on CDs or
DVDs
Photos composed of many
pixels of color
Photos stored on removable
memory card
Other Input Sources
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Video Input

Digital video consists of
series of still frames



Displayed rapidly enough to
give illusion of motion
Web cam used to transmit
video over the Internet
Can capture video from
analog sources with video
capture card
Other Input Sources
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Computer Screen Technology





Computer screens
Printers
Voice output
Music output
Microform

Screen is part of computer’s
monitor



Screen output known as soft
copy
Intangible and temporary
Common forms



Cathode ray tube (CRT)
Flat-panel screens
Smart displays
Output: Information for the User
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CRT Screens

Display text and graphics




Most are in color
Some monochrome monitors
are used in applications that
have no need for color or
graphics
Graphics card converts
signals from the control unit
into the image the user sees
Factors affecting
performance
Factors Affecting Performance

Scan rate


Resolution (clarity) of screen



Measured in pixels- more pixels, the
higher the resolution
Graphics standards exist
Dot pitch



Image refresh rate
The amount of space between dots
The smaller the dot pitch, the
sharper the image
Video memory

A high-speed form of RAM installed
on graphics card
Output: Information for the User
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Graphic Standards

Agree on resolutions, colors, other issues
related to displaying graphics
 Super
Video Graphics Adapter (SVGA) is most
common standard
 Provides
display
800 (horizontal) x 600 (vertical) pixels on the
 Other
varieties of SVGA exist
 Support 16 million colors
 The
number of colors that can be displayed depends on
amount of video memory
Display screens
Flat-Panel Screens
 LCD Technologies
 Smart displays

 Based
on flat-panel technology
 Each contains its own processor
 Wireless transmitter-receiver allows user to control
desktop from anywhere in the house
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


Produce information on
paper output~ hard copy
Orientation~ Portrait,
Landscape
Two ways of printing


Impact printer
Nonimpact printer
Printers
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Impact Printers

Impact Printers




Physical contact with paper
Line printer
Used for lengthy reports
Nonimpact Printers



Dot-matrix printer


Has print head consisting of
one or more columns of pins
Pins form characters and
images as pattern of dots
Places an image on a page
without physically touching the
page
Laser printer


Uses light beam to help transfer
images to paper
High-quality, high speed
Ink-jet printer



Sprays dots of ink from jet
nozzles
Requires high-quality paper so
ink does not smear
Less expensive than laser
printers
Impact printer and Nonimpact printer
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Voice Output
Voice synthesizers convert data to vocalized
sounds
 Two approaches

Synthesis by analysis - analyzes actual human voice,
records and plays back as needed
 Synthesis by rule - uses linguistic rules to create
artificial speech


Used in automated telephone-based customer
service applications

Useful when an inquiry would be followed by a short
reply, such as a balance inquiry
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Music Output

Multimedia clips, games, videos include sight and
sound
Speakers placed on side of monitor
 Powered sub-woofers produce low-frequency sounds


Musical Instrument Digital Interface (MIDI)
Rules for connecting musical instruments, synthesizers,
and computers
 Allows users to set up home studios that rival
capabilities of professional recording studios

Return
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Computer Output Microform (COM)

Output of photographically
reduced images on microfilm
or microfiche




Microfilm - images stored on
continuous roll of film
Microfiche - images stored in
rows and columns on a card
Needs special reader
Common uses


Libraries store back issues
of periodicals
Businesses store large
volumes of historical records
Return
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Terminals
Combine input and output capabilities
 Dumb terminal

 Keyboard
for input and monitor for output
 No processing capability

Intelligent terminal
 Has

limited memory and a processor
Point-of-sale (POS) terminal
 Captures
place
retail sales data when transaction takes
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Business Graphics

Video Graphics
A powerful way to impart
information




Colorful graphics, maps, and
charts help managers compare
data, spot trends, and make
quicker decisions
As underlying data changes,
charts and graphs are instantly
updated
Computer Graphics
A series of video images


Displayed rapidly to give the
impression of motion
Used extensively in television
Also used in computer and
arcade video games
Computer-aided design/computer-aided
manufacturing (CAD/CAM)
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Computer-Aided Design/
Computer-Aided Manufacturing
Creates two- and
three-dimensional
designs
 Performs
engineering tests
such as stress tests
 Serves as bridge
between design and
manufacturing

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Ethics and Data
Once data is in computer, there are many ways
it can be used
 Ethical issues to ponder

 Is
it ethical to use a computer to alter photographs?
 Is it ethical to erase e-mail messages that may be
of interest to a party in a lawsuit?
 Is it ethical to use someone else’s data for your
purposes?
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Objectives







Describe the user relationship with computer input and
output
Explain how data is input into a computer system and
differentiate among various input equipment
Describe how a monitor works and the characteristics that
determine quality
List and describe the different methods of computer output
Differentiate among different kinds of printers
Explain the function of a computer terminal and describe the
types of terminals
Describe the ethical considerations involved in handling
computer data
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